Operation in a submarine well



United States Patent 3,346,045 OPERATION IN A SUBMARINE WELL Richard P. Knapp and Jerome D. Goodrich, IL, New

Orleans, La., assignors, by direct and mesne assignments, to Esso Production Research Company, a corporation of Delaware Filed May 20, 1965, Ser. No. 457,310 20 Claims. (Cl. 166-.5)

ABSTRACT OF THE DISCLOSURE Tubing which is coiled on a spool or reel is propelled into a well by inserting the free end of the tubing, which is provided with a piston, into the well and then imposing fluid pressure against the piston on the free end, thereby propelling the tubing into the well, the tubing extending from a selected point in the well to an accessible location at earth or water surface, if the well is an underwater well.

The present invention is directed to operation in a well drilled to penetrate hydrocarbon-productive subsurface formations. More particularly, the invention is concerned with operations in a submarine well drilled to penetrate hydrocarbon-productive strata. In its more specific aspects, the invention is concerned with well operations wherein a well is completed on bottom in a body of water.

The present invention may be briefly described as a method of conducting operations in a well which may be completed on water bottom and having a conduit forming a passageway extending into said well and extending at least to an accessible point remote from said well of which at least a portion of the conduit is curved. The invention is broadly directed to operations in any well, onshore or offshore. In accordance with the present invention, there is inserted into the well, which may be cased, or into the conduit at an accessible point, the free end of a continuous pipe string having a length sufiicient to reach at least from the accessible point to a selected point in the conduit. The pipe string is then propelled into the conduit by exerting fluid pressure against the pipe string.

The present invention is also concerned with apparatus for conducting operations in a well wherein the well has a conduit forming a passageway extending from a remote accessible point to a selected point in the well with a por tion of the conduit being curved. The apparatus comprises a continuous length of pipe having a free end and adapted to extend in the conduit from the accessible point to a selected point. A piston is provided on the free end of the pipe and means are provided for exerting fluid pressure against the piston whereby the pipe is propelled through the conduit by the fluid pressure. The piston may be a rigid piston or it may be a deformable piston. Where the piston is deformable, it may be constructed of natural or synthetic rubber or other suitable deformable material. Thus, the piston may be constructed of flexible, metallic leaves which may flex or may slidably move one upon the other.

The pipe string having the piston arranged on it may suitably be provided with buoyancy by attaching to the pipe string a sutficient quantity of a material having a density less than that of the fluid in the conduit. Likewise, buoyancy may be provided by making the pipe string with a double wall spaced apart with an annular void space.

The present invention will be further illustrated and described by reference to the drawings in which FIGS. 1 and 1A illustrate a well completed on bottom in a body of water, showing the curved conduit and the running in of the pipe string;

3,346,45 Patented Get. 10, 1957 merals will identify identical parts of a best mode and embodiment, numeral 11 identifies a body of water in which a well generally indicated by the numeral 12 is completed on water bottom 13. A well casing 14, which is cemented in place by usual techniques, is arranged in the well 12, and attached to the well casing 14 by flange members 15 is an underwater Christmas tree generally indicated by the numeral 16. The Christmas tree 16 is suitably closed on its open end by flanged member 17. It will be noted that the well 12 is completed substantially below water level 18.

Connected to the Christmas tree 16 are a plurality of flowlines 19 and 20 which in turn connect respectively to tubing or pipe strings 22 and 23 which extend into the well to one or more hydrocarbon-productive strata (not shown) from which oil and/ or gas may be obtained. The

tubing strings 22 and 23 may suitably be interconnected at one or more points intermediate their ends for workover operations and the like. Flowlines 19 and 20 extend to a remote platform or support 24 which may be a floating platform supported in the body of water 11 by buoyancy means 25 or the platform 24 may be supported by the bottom 13. Platform or support 24 may be 'located onshore if desired. The flowline 20 is suitably closed by a removable cover 20a while the flowline 19 is suitably closed by a removable stufling box 26 into which extends a continuous length of pipe string 27 which is unreeled from a reel 28. The reel 28 connects by a conduit 29 to a tank 30 which in turn connects by conduit 31 to pump 32, which connects by line 33 to the flowline 19.

The continuous length of pipe 27 is provided with a piston member 34 (see FIG. 1A) on its free end 35, but the piston may be arranged at another point on the pipe 27 rather than on the free end.

The continuous length of pipe 27 is constructed of substantially rigid, small diameter pipe. By substantially rigid is meant that the pipe will support its own Weight; but, this does not mean that the pipe does not have substantial flexibility which allows it to traverse bends and curves in the flowline 19.

Although not shown, the reel 23 may be provided with a device for straightening the pipe 27 as it is fed olf or on to the reel, either into or out of the flowline 19. Such straightening devices are well known in the art.

Referring now to FIG. 2, the tubing 22 is shown in a vertical position as in the well 12 with the pipe string 27 provided with a deformable piston 34. Fluid pressure is exerted against the piston 34, which causes the continuous pipe to move through the tubing 22 with fluid in the tubing 22 being displaced upwardly through the pipe 27.

In FIG. 3, the tubing 22 is shown with a sand bridge 36, and it is desirable to wash out the sand bridge. In this instance, fluid flowed down into the pipe 27 is directed against the bridge 36 under sufficient pressure to deform the piston 34 and allow fluid to be returned up the annulus 37 as indicated by the arrows.

Referring to FIG. 4, pipe 27 has arranged on the free 3 end 35 thereof, a piston 34a which is constructed of rigid material. The piston 34:: is provided with a plurality of passageways 38, each having a check valve 39 arranged therein to allow fluid in the tubing 22 to be displaced upwardly through the passageway 38 and check valve 39.

In FIG. 5, a cross section of the pipe 27 is shown having arranged around it a low density material 40 to provide buoyancy to the pipe 27 and also to serve as an antifriction means. Thus, the low density material may 'suitably be a polyolefin, such as polypropylene, having a density lower than that of the pipe 27. The low density material provides buoyancy to the pipe 27 and also serves as an anti-friction device. The low density material may be wrapped around the pipe 27 or it may be formed around the pipe 27 or otherwise attached thereto. The buoyancy means 40 may be applied over the entire length of the pipe, or if desired, be placed along the pipe at spaced apart intervals.

Referring now to FIG. 6, the pipe 27 is shown in the flowline 19 with a deformable piston 34. In this instance, centralizers such as 41 are arranged on the pipe 27 to lessen friction. Although only one centralizer is shown, a plurality of spaced-apart centralizers may be employed.

Referring now to FIGS. 7 and 7A, the pipe 27a has arranged thereon a deformable piston 34. In this instance, the pipe 27a has spaced-apart double walls 42 which provide buoyancy to the pipe 27. The double Wall construction may be continuous or in spaced-apart relation so as to form separate pontoons along the length of the pipe string as shown in FIG. 7A.

In the practice of the present invention, referring now to FIGS. 1 to 7A, inclusive, the continuous pipe string has its free end inserted in the flowline 19. Thereafter, fluid is pumped through line 33 by pump 32 from tank 30 against piston 34. This causes the pipe 27 to be propelled into the flowline 19 around the curves or bends, and thence downwardly into the tubing 22. The amount of pressure employed against piston 34 is suflicient to propel the pipe 27 into the well, as shown, and to unreel the pipe 27 from the reel 28. Fluid in the flowline 19 and tubing 22 is displaced up the fluid passageway 43 and then back through conduit 29 into tank 36 for recirculation.

Alternatively, when operations are conducted such as :shown in FIG. 3, the fluid will be displaced up the annulus 37 and may be discharged from the flowline 19. In this instance, fluid would be flowed down through :the pipeline 27 and up the annulus 37, which would necessitate reversing the pump 32 or providing a separate pump.

The present invention is quite advantageous and use- :ful in that wells may be completed and serviced using a continuous tubing string which may be suitably arranged on a reel and propelled into a well by fluid pressure. Heretofore, it had not been known that a continuous tubing .string may be propelled into a well by fluid pressure.

When the continuous pipe string is to be removed from the well, power may be applied to the reel 28 to withdraw the continuous pipe string from the well. Once the continuous pipe string is run into the Well, it may be used for sand washing, as has been described, circulation, stimulation, cementing, acidizing, or for performing other completion or workover operations by circulating fluid or liquid up or down the continuous pipe string, or by reverse circulation. Likewise, the continuous pipe string may be used for continuous production of fluids such as oil or gas from the well. In any event, fluids such as liquids or gases may flow through the continuous pipe string or through the annulus defined by the continuous pipe string and flowline.

In the present invention, the tubing string or flowline forms a continuous conduit having a fluid passageway therethrough.

While the present invention has been described and illustrated for operation with a flowline and tubing string, it is understood that the invention may be used with a plurality of flowlines and tubing strings. Likewise, the tubing strings 22 and 23 may be interconnected at the well head or intermediate their ends with one string being used for servicing operations and the other for producing operations.

The invention has been described and illustrated by reference to submarine well operations. However, in its broader aspects, the invention is applicable to operations in any well wherein a continuous pipe string is to be run therethrough since, in accordance with the present invention, a continuous pipe string is propelled into a well solely by fluid pressure. This is quite advantageous and useful in that by exerting fluid pressure to propel the continuous pipe string into the well, the continuous pipe string is maintained under tension, which serves to prevent kinking or corkscrewing of the continuous pipe string as it is being run into the Well. It is therefore contemplated that the present invention is broadly applicable to running a continuous pipe string in a well by exerting fluid pressure preferably against the free end of the continuous pipe string.

The nature and objects of the present invention having been fully described and illustrated and the best mode and embodiment thereof set forth, what We wish to claim as new and useful and secure by Letters Patent is:

1. A method for conducting operations in a well having a conduit forming a passageway extending into said well, which comprises inserting into said conduit from a reel a continuous pipe string having a free end and a length suflicient to reach from said reel to a selected point in said conduit, and then propelling said pipe string through said conduit by fluid pressure exerted against said free end.

2. A method for conducting operations in a well having a conduit forming a passageway extending into said well and extending at least to an accessible point, which comprises inserting into said conduit from a reel a continuous pipe string having a free end and having a length sufiicient to reach at least from said reel at said accessible point to a selected point in said conduit, and then propelling said pipe string through said conduit by fluid pressure exerted against said free end.

3. A method for conducting operations in a submarine well completed on water bottom and having a conduit forming a passageway extending into said well and extending at least to an accessible point remote from said well, at least a portion of said conduit being curved, which comprises inserting into said conduit at said accessible point from a reel a continuous pipe string having a free end and a longth sufficient to reach at least from said reel at said accessible point to a selected point in said conduit, propelling said pipe string through said conduit by fluid pressure exerted against said free end, and flowing fluid through said pipe string.

4. A method in accordance with claim 3 in which the conduit contains fluid and said fluid is flowed through said pipe string.

5. A method in accordance with claim 3 in which the fluid flowed through said pipe string is introduced at said accessible point.

6. A method in accordance with claim 3 in which the fluid flowed through said pipe string is from said well.

7. A method in accordance with claim 3 in which the fluid flowed through said pipe string is introduced at said accessible point and is returned to said accessible point through said conduit.

A method for conducting operations in a submarine Well completed on water bottom and having a conduit forming a fluid passageway extending into said well and extending at least to an accessible point remote from said well, at least a portion of said conduit being curved,

7 which comprises inserting into said conduit at said ac cessible point from a reel a continuous pipe string having a free end and provided with a piston on its free end and having a length sufiicient to reach at least from said reel at said accessible point to a selected point in said conduit, and then propelling said pipe string through said conduit by fluid pressure exerted against said piston.

9. A method for conducting operations in -a submarine well completed on water bottom and having a conduit forming a fluid passageway extending into said well and extending at least to an accessible point remote from said well, at least a portion of said conduit being curved, which comprises inserting into said conduit at said accessible point from a reel a continuous buoyant pipe string having a free end and having a length sutficient to reach at least from said reel at said accessible point to a selected point in said conduit and then propelling said pipe string through said conduit by fluid pressure exerted against said free end.

10. A method in accordance with claim 9 in which buoyancy is provided to said pipe string by attaching thereto a material having a density less than that of the pipe string. 7

11. A method in accordance with claim 10 in which buoyancy is provided to said pipe string by forming an annular wall spaced from the outer wall of said pipestring.

12. A method for conducting operations in a submarine well completed on water bottom and having a conduit forming a fluid passageway extending into said well and extending at least to an accessible point remote from said well, at least a portion of said conduit being curved, which comprises inserting into said conduit at said accessible point from a reel a continuous pipe string having a free end and provided with a piston on said free end and having a length sufficient to reach at least from said reel at said accessible point to a selected point in said conduit, and then propelling said pipe string through said conduit by pumping fluid into said conduit against said piston under a suflicient pressure.

13. A method in accordance with claim 12 in which the accessible point is a platform extending above water surface.

14. In combination, apparatus for conducting operations in a submarine well completed on water bottom and having a conduit forming a passageway extending into said well and extending at least to an accessible point remote from said well, at least a portion of said conduit being curved, which comprises a continuous length of pipe having a free end and adapted to extend in said conduit from a reel at said accessible point to a selected point in said conduit, a piston on the free end of said pipe, and means for exerting fluid pressure against said piston whereby said pipe is propelled through said conduit by said fluid pressure.

15. Apparatus in accordance with claim 14 in which the piston is deformable.

16. Apparatus in accordance with claim 14 in which the pipe string is buoyant.

17. Apparatus in accordance with claim 14 in which the pipe string has spaced apart double walls.

18. Apparatus in accordance with claim 14 in which the pipe string has a material having a density less than that of the pipe string attached thereto to provide buoyancy to said pipe string.

19. A method for conducting operations in a well which comprises inserting into said well a continuous pipe string having a free end and a length suflicient to reach from a reel to a selected point in said well and then propelling said pipe string into said well by fluid pressure exerted against said free end.

20. A method in accordance with claim 19 in which a piston is arranged on said pipe string and said fluid pressure is exerted against the piston.

References Cited UNITED STATES PATENTS 2,548,616 4/1951 Priestman et al 103 2,567,009 9/ 1951 Calhoun et al. l66462 2,805,718 9/1957 Tausch 16646 2,810,442 10/1957 Tausch 166-77 3,022,822 2/ 1962 McStravick et 'al. 166-.5 X 3,070,167 12/1962 Loy 166153 3,116,793 1/ 1964 McSt-ravick 16677 X ERNEST R. PURSER, Primary Examiner.

CHARLES E. OCONNELL, Examiner.

R. E. FAVREAU, Assistant Examiner. 

1. A METHOD FOR CONDUCTING OPERATIONS IN A WELL HAVING A CONDUIT FORMING A PASSAGEWAY EXTENDING INTO SAID WELL, WHICH COMPRISES INSERTING INTO SAID CONDUIT FROM A REEL A CONTINUOUS PIPE STRING HAVING A FREE END AND A LENGTH SUFFICENT TO REACH FROM SAID REEL TO A SELECTED 